Ex. 4. While covering a distance of 24 km, a man noticed that after walking for
1 hour and 40 minutes, the distance covered by him was
5/7 of the remaining distance.
What was his speed in metres per second ?
Answers
Answer:
D=24km=24000 meters
d=5/7(D-d)
d=5/7(24000-d)
d=10000
1 hour 40 minutes =100 minutes = 6000 seconds
6000 seconds *X meters/second =10000 meters
X=10000/6000=5/3=1 2/3rds
His speed was 1 and 2/3rds meters per second, approximately 1.666… m/s
Answer:
Lets take the things given first
Total distance = 24km
D covered=\dfrac{5} {7} of D left
Time walked = 1hr 40 min = 53 hr
Lets take the speed as ‘ x ’kmph
Distance covered= speed X time
Distance= x X 53 hr
Distance= 5x3 km
remaining=total- covered
=(24- 5x3 )
We know that
distance covered= 57 distance left
5x3=57(24−5x3)
5x3=57 X 72−5x3
Further equating
7x=72−5x
12x=72
x =6 kmph
x =6 x 518 m/s
x = 53 m/s
x= 1.666….. m/s✍️✍️
2 method
D=24km=24000 meters
d=5/7(D-d)
d=5/7(24000-d)
d=10000
1 hour 40 minutes =100 minutes = 6000 seconds
6000 seconds *X meters/second =10000 meters
X=10000/6000=5/3=1 2/3rds
His speed was 1 and 2/3rds meters per second, approximately 1.666… m/s